Method for driving a gas discharge panel

ABSTRACT

A method for driving a gas discharge panel having plural display electrode pairs and plural select electrodes arranged to intersect the display electrode pairs. The intersections of the select electrodes and one display electrode in each display electrode pair define a plurality of select cells and each display electrode pair defines plural display cells between the display electrodes at positions adjacent to respective ones of the select cells. The method includes the steps of applying a firing voltage across a display electrode pair to generate discharges in the display cells defined by the display electrode pair, generating a discharge in select cells corresponding to non-selected display cells, thereby eliminating the wall charge in and erasing the non-selected display cells, and applying a sustaining voltage across the display electrode pair to maintain discharges in the selected display cells.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved method for driving a gasdischarge display panel, and more particularly, a method for stablydriving a surface discharge or monolithic type gas discharge panelproviding a wide operating margin.

2. Description of the Related Art

In gas discharge panels, known as plasma display panels, surfacedischarge or monolithic type display panels utilize lateral dischargesbetween adjacent electrodes. Basically, as is disclosed in U.S. Pat. No.3,646,384, issued to F. M. Lay, in a monolithic gas discharge panel ofthis type, the electrodes are disposed only on one substrate of a pairof substrates and are separated by a dielectric layer or layers. Theelectrodes on opposite sides of a dielectric layer are arranged tointersect and the intersections define discharge cells. The pair ofsubstrates oppose each other and define a gap or space filled with adischarge gas. This structure provides the advantages of alleviating therequirement of an accurate gap spacing and the realization ofmulti-color displays which are created by coating the internal surfaceof the non-electrode bearing substrate with an ultraviolet rayexcitation type phosphor. With the structure of the conventional panel,however, satisfactory panel life and operating margin could not beobtained beacuse the dielectric layer is damaged by a concentration ofthe discharge current at portions of the dielectric layer correspondingto the edges of the electrodes.

To prevent damage to the dielectric layer and to assure long panel lifeand stable operation, the inventors of the present invention havedeveloped a three-electrode type AC surface discharge panel havingseparated select (or write) and display cells, as disclosed inco-pending U.S. patent application Ser. No. 640,579, filed Aug. 14,1984, now U.S. Pat. No. 4,638,218 for GAS DISCHARGE PANEL AND METHOD FORDRIVING SAME, which is assigned to the assignee of the presentapplication. The panel structure disclosed in application Ser. No.640,579 is called a three-electrode type AC surface discharge panelbecause each picture element, comprising a select cell and a displaycell, is defined by the intersection of a select electrode with a pairof parallel display electrodes. The select cell is defined by theintersection of the select electrode and one of the display electrodesin the display electrode pair, and the display cell is defined by thespace between the display electrodes adjacent to the select electrode.In addition to assuring long panel life and stable operation, athree-electrode type surface discharge panel provides an internaldecoding function by employing multiple connections of the displayelectrode pairs, thereby simplifying the operation of driving the paneland the driving circuitry. However, the driving method disclosed inapplication Ser. No. 640,579 does not allow the panel to be addressedline-by-line if the display electrodes are multiply connected.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide an improveddisplay addressing method for a three-electrode-type AC surfacedischarge panel which provides a large operating margin.

It is another object of the present invention to provide a drivingmethod which stably addresses a three-electrode type monolithic displaypanel with a low driving voltage.

It is a further object of the present invention to provide a drivingmethod for a three-electrode type monolithic panel having multiplyconnected display electrodes which provides for addressing with aline-by-line addressing sequence.

It is a still further object of the present invention to provide amethod for driving a three-electrode type monolithic panel using asimplified and economical circuitry.

A method according to the present invention, for driving a monolithicgas discharge panel having plural picture elements, each picture elementbeing formed of a disp1ay ce11 and a select cell, comprises the steps offiring the display cells defined by one pair of display electrodes, orline, by applying a firing voltage across the pair of parallel disp1ayelectrodes forming the display cell line and erasing the discharges innon-selected display- cells, i.e., display cells which do not form apart of the intended display, by applying an erase voltage pulse to theselect electrodes defining the select cells which form pairs with thenon-selected display cells.

More particularly, the present invention relates to a method for drivinga three-electrode type monolithic gas discharge panel. The display panelincludes an electrode support substrate and a cover substrate. Displayelectrode pairs are arranged on the electrode support substrate and anelectric or insulating layer is formed over the disp1ay electrodes.Plural select electrodes are arranged on the dielectric 1ayer so thatthey cross the display electrode pairs, and an insulating layer isformed over the select electrodes and the dielectric layer; the coversubstrate opposes the electrode support substrate to define a gas-filleddischarge space or gap. Select cells are defined by the intersections ofthe select electrodes and one e1ectrode of each pair of displayelectrodes, and display cells are defined at a plurality of pointsbetween each pair of disp1ay electrodes corresponding to theintersections of the select electrodes and the display electrodes. Eachselect cell and display ce11 pair form a picture element, the pluralpicture elements in a panel being arranged in a matrix. The method ofthe present invention comprises the steps of generating discharges,which are accompanied by the generation of wall charges, at all of thedischarge cells defined between one pair of display electrodes byapplying a firing voltage which exceeds a discharge start voltage acrossthe pair of display electrodes, and selectively applying a voltage tothe select electrodes which define the select cells of the non-selectedpicture elements to erase or remove the wall charge in the non-selecteddisplay cells. A discharge is maintained in the display cell of theselected picture elements by the application of an AC sustaining vo1tageacross the display electrode pair.

Another feature of the present invention is the application of anasymmetrical composite sustaining voltage waveform. The asymmetricalcomposite sustaining voltage waveform supplies, to the display electrodein each display electrode pair which defines select cells at theintersection of the one display electrode and the select electrodes, asustaining voltage having a larger amplitude than the sustaining voltagesupplied to the other display electrode in a display electrode pair.

A further feature of the present invention is that the generation ofdischarges in all of the display cells defined by one pair of displayelectrodes is sequentially carried out for the plural pairs of displayelectrodes in a panel and that the erasing of the non-selected displaycells of each line is carried out at a time which lags behind thegeneration of discharges by at least the amount of time between thegeneration of discharges in one line and the generation of discharges ina next line.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view showing the structure of a monolithic gasdischarge panel to which a driving method of the present invention isapplied;

FIG. 2 is a plan view showing the electrode arrangement of the panelshown in FIG. 1;

FIG. 3 is a cross-sectional view of a panel along the line III--III' inFIG. 2;

FIG. 4 is a schematic diagram showing an electrode configuration and thedischarge cell arrangement for describing the driving method of thepresent invention;

FIGS. 5(a)-(k) are examples of driving voltage waveforms used in themethod of driving a gas discharge panel according to the presentinvention;

FIG. 6 is a schematic diagram showing multiply connected electrodes;

FIGS. 7(a)-(l) are voltage waveforms for driving a panel having themultiple electrode connections shown in FIG. 6;

FIGS. 8(a) and (b) are schematic diagrams of panels in which thesustaining electrodes are multiply connected for describing anaddressing sequence for such panel;

FIG. 9 shows examples of driving voltage waveforms corresponding to theaddressing sequence shown in FIGS. 8(a) and (b);

FIG. 10 is a graph of experimental data showing the operating margin ofa panel operated with the driving method of the present invention;

FIGS. 11(a)-(h) are schematic diagrams of panels in which the sustainingelectrodes are multiply connected for describing an addressing sequencefor such panels in accordance with a modified embodiment of the methodof the present invention;

FIGS. 12(a)-(j) are examples of driving voltage waveforms used in theaddressing sequences shown in FIG. 11;

FIG. 13 is a schematic diagram of a panel in which the sustainingelectrodes are multiply connected and typical driving circuitry forperforming the driving method of the present invention; and

FIG. 14 is a graph of the operating margin achieved with the addressingsequences shown in FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1, 2 and 3, a plurality of pairs of displayelectrodes 11 are arranged in a vertical direction on a lower glasssubstrate 10, the lower glass substrate 10 functioning as an electrodesupporting substrate. Select electrodes 13, extending in a horizontaldirection, and separator electrodes 14, also extending in a lateraldirection, are separated from the display electrodes 11 by a dielectriclayer 12 made of a low melting point glass. A surface layer 15 formed offor example, magnesium oxide (MgO) is formed on the select and separatorelectrodes and the dielectric layer 12 in a thickness of severalthousand angstroms. A gas space 17, defined between the surface of theinsulating layer 15 and an upper glass substrate 16, is evacuated andfilled with a discharge gas, i.e., a gas capable of being ionized. Aphosphor material which emits colored light when excited by ultravioletrays may be provided on the internal surface of the upper glasssubstrate 16.

Each display electrode pair 11 comprises two adjacent displayelectrodes, e.g., X1, Y1 and X2, Y2, as is further apparent from FIG. 2,and each display electrode pair has discharge areas x and y whichproject from the adjacent sides of a pair of display electrodes 11.Select electrodes 13, e.g., W1, W2, are transverse to the displayelectrodes 11 and intersect the display electrodes 11 in the approximatearea of the discharge areas x and y. Separator electrodes 14, for use ina floating condition, are parallel to the select electrodes 13 but donot intersect the discharge areas x and y; the separator electrodes 14are provided on the opposite side of the select electrodes 13 from thedischarge areas x and y. Thus, select cells T are defined by, forexample, the intersecting point of the select electrodes W1, W2 and thedisplay electrodes Y1, Y2, and display cells K are defined by the areabetween the discharge areas x, Y. A picture element (PIXEL)corresponding to one dot is formed by a select cell T in a correspondingdisplay cell K and is defined by the three types of electrodes X, Y andW.

In a three-electrode type discharge panel, the creation of a dischargein a selection cell T affects the adjacent display cell due to thecoupling of space charges or the spread of wall charges. In particular,a discharge in a select cell T is accompanied by the generation of wallcharges on the surface of the insulating layer 15 at a positioncorresponding to the select cell T. The wall charges accumulate andextend over the surface of the insulating layer 15 to the approximateposition of a corresponding display cell K. Therefore, when a sustainingvoltage is applied to the display electrode pair, a discharge isgenerated at the display cell, as described in application Ser. No.640,579. However, the discharge in the display cell K can be erased bygenerating a discharge in the corresponding select cell T; the dischargein the select cell T causes the space charges, and wall charges in thedisplay cell K to generate a self-discharge which consumes the wallcharges, and thus erases the display cell K.

The driving method of the present invention relates to an erasingaddress sequence for erasing discharges in non-selected display cells.In the method of the present invention all of the display cells definedby a pair of display electrodes 11 are fired by applying a firingvoltage across the display electrode pair 11. The non-selected displaycells are erased by creating discharges in the select cellscorresponding to the non-selected display cells to perform a vicinityerasing function. The method of the present invention will be explainedin detail with reference to FIGS. 4 and 5.

FIG. 4 is a schematic diagram of an example of the electrodeconfiguration in a three-electrode type monolithic display panel havingfour (2×2) display cells (PIXELS). Two X display electrodes, connectedin common and designated X₀, and the two Y display electrodes,designated Y₁ and Y₂, form display electrode pairs with respective onesof the electrodes in the display electrode group X₀. Two selectelectrodes W₁ and W₂ are separated from the display electrodes bydielectric layer and arranged so that they intersect the displayelectrodes. Select cells T₁ -T₄, for generating discharges, are formedat the intersections of the display electrodes Y₁, Y₂ and the selectelectrodes W₁, W₂, and display cells K₁ -K₄, for displaying information,are defined between the display electrode pairs in the vicinity of theselect cells T₁ -T₄, respectively.

FIGS. 5(a)-(e) illustrate voltage waveforms which are applied to theelectrodes X₀, W₁, Y₁, W₂, and Y₂ respectively. FIGS. 5(f) and (g)illustrate composite voltage waveforms applied across the pairs ofdisplay electrodes, Y₁ and X₀, and Y₂ and X₀, and FIGS. 5(h)-(k)illustrate equivalent voltage waveforms for display cells K₁ -K₄, i.e.,the voltage which is accumulated on the wall surface of the dielectricmaterial during the discharges of the display cells K₁ -K₄. Timeincreases from left to right in FIGS. 5(a)-(k).

The method of the present invention for applying the voltage waveformsshown in FIGS. 5(a)-(e) is as follows: At time A₁, a firing pulse F₁,having a voltage V_(F) is applied to display electrode Y₁ and a voltagepulse, having a voltage (-V₁) is applied to display electrode X_(o).Thus, a composite vo1tage value of |V₁ |+|V_(F) |, which exceeds thefiring voltage of the display cells defined by the pair of electrodesX₀, Y₁, is applied across these electrodes. As a result, discharges areinitiated in display cells K₁ and K₂ (i.e., a first line of displaycells). The discharges in display cells K₁ and K₂ generate wall chargeswhich are accumulated on the surface of the insualting layer 15. Thevoltages of the wall charges are illustrated in FIGS. 5(h) and (i).

At time E₁, a selection pulse P₁ is applied to select electrode W₁. Theselection pulse P₁ has a voltage amplitude V_(a) and a pulse width whichis equal to the pulse width of a sustaining voltage pulse defined by thecomposite voltage waveform Y₁ -X₀ shown in FIG. 5(f). The amplitudeV_(a) of the select pulse P₁ is set so that the value of a compositevoltage, defined by the absolute value of V_(a), plus the absolute valueof the voltage (-V₂) of a sustaining pulse Q₁ which is applied to thedisplay electrode Y₁, is large enough to generate a discharge in selectcell T₁. At time E₁, a wall charge generated by the discharge indischarge cell K₁ spreads over the surface of the insulating layer 15 inthe region of the select cell T₁, and the wall charge aids in thegeneration of a discharge in select cell T₁. Therefore, when displaycell K₁ is firing or discharging, a discharge can be generated in selectcell T₁ by a lower voltage than in the situation where display cell K₁is not firing.

When the pulses P₁ and Q₁ are applied to select electrode W₁ and displayelectrode Y₁, respectively, a discharge occurs in select cell T₁ at therising edge of the pulses P₁ and Q₁, i.e., at the time E₁. The dischargein select cell T₁ neutralizes some of the wall charge accumulated on thesurface of the dielectric layer 15 in the adjacent display cell K₁.Further, the wall charge generated in the select cell T₁ creates aself-discharge in the select cell T₁, due to the avalanche phenomenon ofthe wall charge, when the composite vo1tatge of pu1ses P₁ and Q₁ falls.The self-discharge further reduces the wall charge in the adjacentdisplay cell K₁, and eliminates the wall charge in the select cell T₁.The attenuation profile of the voltage of the wall charge in the displaycell K₁ is indicated in the circle R in FIG. 5(h). Further, immediatelyafter the application of the select pulse P₁, no voltages are applied tothe display cell K₁, and the self-discharge generated at the fallingedge of the pulses applied to the select cell T₁ brings the wall chargein the display cell K₁ to zero as shown in FIG. 5(h). To assure theattenuation of the wall charge, the sustaining voltage for the displayelectrode X₀ is held at zero volts during the period d₁ shown in FIG.5(f). Thus, a discharge in the display cell K₁ can be accurately erased.

Meanwhile, the wall charge accumulated on the surface of the dielectriclayer 15 in display cell K₂ by the discharge occurring therein at timeA₁ is maintained on the dielectric layer 15 since a selection pulse isnot applied to select electrode W₂ defining select cell T₂. Accordingly,when a sustaining voltage is applied across electrodes X₀ and Y₁, afterthe application of the select pulses P₁ and Q₁, a discharge is generatedand maintained in display cell K₂. This completes the addressing of thefirst line so that display K₂ is firing or selected, and so that displayK₁ is not firing or non-selecting.

To address the second line, a firing pulse F₂ is applied across thedisplay electrode pair X₀ and Y₂ and the time A₂, thereby generatingdischarges in display cells K₃ and K₄. In the case of the second line,where it is desired to select display cell K₃, a selection pulse P₂ isapplied to the select electrode W₂ at time E₂ so that a pulse having acomposite voltage |V_(a) |+V₂ | is applied to select cell T₄. Thisgenerates a discharge in select cell T₄ thereby eliminating the wallcharge in display cell K₄ and erasing display cell K₄ during the periodd₂ when the sustaining voltage applied to display cell K₄ is zero. As aresult, the discharge is maintained only in display cell K₃.

A second embodiment of the present invention is a method for driving asurface display panel having multiply connected display electrode pairs,which provide an internal decoding function, with reference to FIGS. 6and 7. FIG. 6 is a schematic diagram of a panel having eight PIXELS(2×4), wherein the display electrode pairs are divided into pluralgroups, i.e., two groups. In particular, electrodes X₁ and X₂ are formedby connecting two adjacent X display electrodes in common, andelectrodes Y₁ and Y₂ are formed by connecting corresponding Y displayelectrodes from each group formed by electrodes X₁ and X₂ in common.Thus, display cells K₁₁ and K₁₂ are defined along the electrode pair(X₁, Y₁), display electrodes K₂₁ and K₂₂ are formed along the electrodepair (X₁, Y₂), display cells K₃₁ and K₃₂ are formed along the electrodepair (X₂, Y₁), and display cells K₄₁ and K₄₂ are formed along theelectrode pair (X₂, Y₂) Further, select cells T₁₁, T₁₂, . . . , T₄₂ areformed at the respective intersecting points of the display electrodesY₁ and Y₂ and the select electrodes W₁ and W₂, the select cells beingadjacent to a corresponding display cell so that discharges in theselect cells affect the wall charges and space charges in thecorresponding display cells.

FIGS. 7(a)-(l) are examples of voltage waveforms utilized to drive apanel having the multiple electrode connections shown in FIG. 6. Inparticular, the waveform shown in FIG. 7 are an example of waveformsused to create a discharge in display cell K₂₂ when a panel having themultiple electrode connections showin in FIG. 6 is in operation,including the presence of fired cells and nonfired cells. The waveformsX₁, X₂, Y₁ and Y₂, shown in FIGS. 7(a)-(d), are applied to the displayelectrodes X₁, X₂, Y₁ and Y₂. The waveforms X₁ -Y₁, X₁ -Y₂, X₂ -Y₁ andX₂ -Y₂, shown in FIGS. 7(e)-(h), are composite voltage waveforms appliedacross the respective electrode pairs, and the waveforms K₂₁ and K₂₂,shown in FIGS. 7(i) and (j) illustrate the voltage of the wall chargeaccumulated on the surface of the dielectric layer 15 in display cellsK₂₁ and K₂₂. Further, the waveforms W₁ and W₂, shown in FIGS. 7(k) and(l), illustrate select pulses applied to the select electrodes W₁ andW₂.

To generate discharges in the display cells formed along the electrodepair (X₁, Y₂), i.e., display cells K₂₁ and K₂₂, firing pulses F₃ and F₄are simultaneously applied to the display electrodes X₁ and Y₂,respectively, at time A₃. The composite voltage pulse having anamplitude of |V₁ |+|V_(w) |, which exceeds the discharge voltage,creates these discharges. After allowing two cycles for the dischargesto stabilize, selection pulses P₃ and Q₃ are applied to electrodes W₁and Y₂, respectively, to generate a discharge in select cell T₂₁, attime E₃. As described above, the wall charge is eliminated in displaycell K₂₁ the cell is removed. The elimination or removal of the wallcharge is shown in the circle R in the vo1tage diagram K₂₁ of FIG. 7(i).However, the wall charge is maintained in display cell K₂₂ and adischarge is generated when a sustaining voltage is applied. Thesustaining voltage must be reapplied to display cell K₂₂ because thevoltage applied to the cell is zero during the period d₃, which occursat the falling edge of the composite voltage pulse P₃ +Q₃, to assureelimination of the wall charge in display cell K₂₁.

The effect of the application of the asymmetrical selection pulses W₄and Q₃ on cells other than those described above are as follows. Selectcell T₄₁ receives the select pulses P₃ and Q₃ and a select discharge isgenerated in select cell T₄₁. Thus, display cell K₄₁ would be erased.However, a supplemental selection pulse r₃ is applied to the sustainingelectrode X₂ immediately after the selection pulses P₃ and Q₃. Thissupplemental selection pulse r₃ has a voltage (-V₁) which is largeenough to generate a redischarge in the display cell K₄₁, therebycontinuing the discharge in display cell K₄₁ and generating a new wallcharge. Display cells K₁₂, K₃₂ and K₄₂, corresponding to selectelectrode W₂, are not disturbed because the select pulse P₃ is notapplied to the select cells corresponding to these discharge cells.Further, the discharge condition of display cells K₁₁ and K₃₁,corresponding to select electrode W₁, to which the select pulse P₃ isapplied, is not changed because the asymmetrical selection pulse Q₃ isnot applied to display electrode Y₁.

One purpose of the second embodiment is to enable the select electrodes,e.g., W₁ and W₂, to be driven by a low voltage integrated circuit (IC)driving element. The asymmetrical select pulses P₃ and Q₃ utilized inthe method of the present invention allow a reduction of voltage levelV_(p) of the select pulse P₃. In particular, since the voltage appliedto select cell T₂₁ has a voltage of |V₂ |+|V_(p) |, the value of thevoltage value (-V₂) of the select pulse Q₃ may have a large peak valuein order to allow a reduction in the voltage V_(P) of the select pulseP₃. For example, the voltages may be as follows: V₂ =-160; V₁ =-100, andV_(F) =80. With these voltages, normal addressing operation has beenattained when V_(P) =20˜50. Accordingly, the select electrodes can bedriven with a voltage of approximately 30 volts by a low voltage IC.

A third embodiment of an improved method for driving a gas dischargedisplay panel in accordance with the present invention will be explainedwith reference to FIGS. 8-10. One feature of the third embodiment isthat each line, or electrode pair, in a panel is sequentially fired, orcaused to discharge, and then subject to an erase/address sequence.FIGS. 8(a) and (b) are schematic diagrams showing the states of 64PIXELS (8×8) in a panel subject to the line address sequence of thethird embodiment of the present invention. In particular, FIGS. 8(a) and(b) sequentially illustrate the line addressing sequence advancing byone line. In FIGS. 8(a) and (b) display cells which are discharging areillustrated by a circle. The display electrodes i (i=1, 2, 3, . . . , 8)are connected in common, with each electrode forming a pair (X_(i),Y_(i)) with a corresponding Y display electrode Y_(i) (i=1, 2, 3, . . ., 8 ), and the line address sequence procedes in ascending order of theelectrode number i.

FIG. 9 illustrates the waveforms utilized in the third embodiment of thedriving method of the present invention, particularly, the lineaddressing sequence shown in FIGS. 8(a) and (b). The waveforms T_(i)shows erasing half-select pulses applied to select electrodes W_(j)(j=1, 2, 3 . . . 8 ), a half-select pulse being the pulse applied to oneof a pair of matrix electrodes when a composite voltage is achieved byapplying pulses to two electrodes. The erasing half-select pulses areapplied to the select electrodes forming select cells adjacent tonon-selected display cells to eliminate the wall charge in thenon-select display cells, thereby performing an erasing/addressoperation. The waveform X_(s) is applied to a selected group of Xdisplay electrodes, e.g., X₁ -X₈, and the waveforms Y₁, Y₇ are appliedto the respective Y electrodes. The waveform X_(n) is applied tonon-selected X disp1ay electrodes (not shown). The difference betweenthe waveforms X_(s) and X_(n) is that the waveform X_(s) includesselective sustaining pulses P_(s) for reversing the polarity of thevoltage of the wall charge in the display cells along the selected Xelectrodes at a time prior to the application of the erase half-selectpulses to the select electrodes W_(i). The voltage pulses V_(xi) andV_(yi) apply a composite voltage which is greater than the firingvoltage across the i-th electrode pair to generate discharges in all ofthe display cells on the i-th electrode pair. For example, the pulsesV_(x3) and V_(y3) generate discharges in all of the cells on the thirdline, i.e., the display electrode pair (X₃, Y₃).

With reference to the third line, electrode pair (X₃, Y₃), by way ofexample, erasing half-select pulse V_(e3) is applied to displayelectrode Y₃ at a time corresponding to the application of the erasinghalf-select pulse t₃. The timing of the pulses T₃ and V_(e3) is delayedby period T_(f3) from the pulses V_(x3) and V_(y3) in order to allow thewall charge in the se1ected cells to stabilize. Further, the erasehalf-selection pulse T₃ is applied to all of the select electrodes W_(j)defining select cells are corresponding to non-selected display cells tobe erased.

The timing of the sequential addressing of the electrode pairs is suchthat the firing pulses V_(x4) and V_(y4) for the fourth line are appliedto the display electrode pair (X₄, Y₄)prior to the erase addressing ofthe third electrode pair.

FIG. 10 is a graph of experimental data illustrating the operatingmargins for the first and third embodiments of the present invention.The horizontal axis represents the voltage of the half-selection pulseapplied to the select electrodes and the vertica1 axis represents thevoltage of the sustaining pulses applied to the display electrodes. Inparticular, the region enclosed by curve I illustrates the operatingrange for the line addressing sequence of the third embodiment of thepresent invention, and the region enclosed by curve II illustrates theoperating range in the erasing address system of the first embodiment ofthe present invention. The data for curves I and II was obtained with apanel having 19,200 PIXELS, i.e., 240 lines (or display electrode pairs)and 80 select electrodes, with a 0.6 mm dot pitch. The X displayelectrodes were connected in 15 groups and the Y display electrodes wereconnected in 16 groups. In the experimental panel the dielectric layer12 separating the display electrodes in the se1ect electrodes had athickness of 12 μm and the surface dielectric layer 15 was formed ofmagnesium oxide (MgO) in a thickness of 0.4 μm. The gas was a mixture ofNe and 0.2 percent Xe at a pressure of 500 Torr. As shown in FIG. 10, awider operating margin is obtained with the line addressing sequence ofthe third emhodiment than with the addressing method of the firstembodiment.

A further example of the addressing method of the present invention willbe explained with reference to FIGS. 11 and 12. FIGS. 11(a)-(h)illustrate various steps in the addressing of a display panel having 9display pairs X_(i) and Y_(i) (i=1,2,3, . . . ,9) divided into 3 groupsof X and Y electrodes, and 5 select electrodes A_(1-A) ₅. In FIGS.11(a)-(h) the various electrodes A_(i), X_(i) and Y_(i) enclosed by adouble circle (⊚) are undergoing an erasing operation, the electrodesenclosed by a single circle (○) are receiving the sustaining voltagepulses for a selected electrode, and the electrodes which are notcircled are receiving the sustaining voltage pulse for non-selectedelectrodes.

FIGS. 12(a)-(j) show waveforms corresponding to the states of thedisplay cells and select cells of the panel shown in FIG. 11. Inparticular, waveforms A₁ -A₅ in (FIGS. 12(a)-(e)) apply selection pulseshaving a positive voltage V_(a) to respective ones of the selectelectrodes A_(1-A) ₅. Waveforms X₁ and X₂, and Y₁ -Y₃ (FIGS. 12(f)-(j))are applied to respective ones of the display electrodes X_(i) andY_(i). Further, an ordinary sustaining voltage waveform is applied tothe selected display electrodes and a sustaining voltage waveform havingcertain pulses extracted therefrom is applied to the non-selecteddisplay electrodes.

With reference to FIG. 11(a), and FIGS. 12(f) and (h)-(j), a write pulseV_(w) is applied across the display electrode X₁, and all of the Yelectrodes forming pairs with the X display electrode Y₁, from the Ydisplay electrode side at a time T₁. The composite voltage |V_(s)|+|V_(w) | generates discharges in all of the display cells along theelectrode pairs formed by display electrode X₁. Then, at time T₂ anerase select pulse, having a positive voltage V_(a), is applied toselect electrode A₁ to generate discharges in select cells 21, 22, and23 formed at the intersections of the display electrode X₁ and selectelectrode A₁. If a discharge is to be maintained at display cell 31,located between the electrode pair (X₁, Y₁) in the vicinity of theselect e1ectrode A₁, a sustained pulse P_(s) is applied to the displayelectrode Y₁ at time T₃. However, at time T₃ the sustaining pulses areextracted from the sustaining vo1tage waveforms supplied to thenon-selected electrodes Y₂ and Y₃. Therefore, the wall charges and spacecharges in display cells 32 and 33 are eliminated by the self-dischargewhich is generated in the select cells 22 and 23 at the falling edge ofthe select pulse applied to the select electrode A₁. As a result, thedischarges in display cells 32 and 33 are erased. At time T₄ sustainingvoltage pulses are applied between all of the X and Y display electrodesto maintain the discharges generated in the display cells formed betweenthe display electrode pairs (X₁ , Y₂), and (X_(l), Y₃) which were noterased.

Thereafter, a select pulse V_(a) is applied to select electrode A₂ attime T₅ in order to generate discharges in select ce11s 24, 25 and 26;however, a sustaining voltage pulse P_(s) is applied to displayelectrode Y₃ to maintain the discharge in display cell 36 at time T₆.Thus, the discharges in the display cells associated with select cells24 and 25 are erased and the display which appears when the nextsustaining voltage pulses applied is shown FIG. 11(e). An explanation ofthe addressing operation for select electrodes A₃, A₄, and A₅ inconjunction with the display electrode pairs formed by display electrodeX₁ will be ommitted to avoid repetition.

The operation of the display cells formed by the display electrode X₂will be described with reference to FIGS. 11(f)-(h). First, all of thedisplay cells along the electrode pairs (X₂, Y₁), (X₂, Y₂) and (X₂, Y₃)are caused to discharge by applying a write pulse across all of theseelectrode pairs from the Y electrode side at time T₇. At this time, thedisplay cells formed by the display electrodes X₁ and X₃ are storing thewall charges formed therein since the sustaining voltage pulses areextracted from the sustaining voltage waveform during theselecting/addressing operation for display electrode X₂, as shown by thecircles 40 in FIG. 12(f). At time T₈, a selection pulse is again appliedto the select electrode A₁ to fire the select cells 27, 28, and 29located at the intersection of select electrodes A₁ and displayelectrode X₂. In order to erase the discharge in the display cell 38associated with select cell 28, a sustaining voltage pulse is notapplied to display electrode Y₂ at time T₉. Thus, the wall charges andspace charges in display cell 38 are eliminated, as shown in FIG. 11(g).Also at time T₉, sustaining voltage pulses are applied to the displaycells located at the intersection of display electrode X₂ and displayelectrodes Y₁ and Y₃, i.e., display cells 37 and 39, in order tomaintain a discharge in these display cells. At time T₁₀, whensustaining voltage pulses are applied to all of the display cells in thepanel, display cell 38 does not discharge, whereas display cells 37 and39 do discharge, as shown in FIG. 11(h).

FIG. 13 illustrates typical high voltage drivers which are provided atthe periphery of a display panel for operation in accordance with theaddressing method of the present invention. In particular, D_(x) andD_(y) are the drivers for driving display electrodes X_(i) and Y_(i),respectively, which output the sustaining voltage pulses having avoltage (-V_(s)) shown in FIG. 12. D_(a) is a driver for driving theselect electrodes A_(i) which outputs the select pulses having a voltageV_(a), as shown in FIG. 12. The Y electrode drivers D_(y) include aswitching element 30 for supplying the write voltage pulse having avoltage V_(W). The circuit configuration of the drivers D_(x), D_(y) andD_(a) is well suited for providing the voltage waveforms shown in FIGS.5, 9 and 12.

FIG. 14 is a graph illustrating the operating margin obtained with theaddressing method discussed with respect to FIGS. 11 and 12. In FIG. 14the horizontal axis represents the amplitude of the select pulse appliedto the select electrodes A_(i) and the vertical axis represents the peakvalue of the sustaining voltage pulses applied to the sustainingelectrodes X_(i) and Y_(i). The area M₁ is an example of the operatingmargin of a prior art addressing method. The area M₂ is the operatingmargin obtained with the method of the present invention as describedwith respect to FIGS. 11 and 12, which is remarkable in that it isgreatly enlarged in the low voltage range of the selection pulse.

It will be understood from the above description of the addressingmethod of the present invention that the wall charge in a display cellis eliminated by generating a discharge in the select cell correspondingto the display cell after the display cell has been fired. The selectcell is fired by applying an erase pulse, and a self-discharge occurs inthe display cell, due to the presence of wall charges, at the fallingedge of the pulse applied to the select cells, thereby consuming thewall charge in the display cell. Accordingly, the wall charges can beeliminated and a discharge in the display cell erased over a wide rangeof sustaining pulse voltages. Moreover, in accordance with the method ofthe present invention, difficulties in firing only selected dischargecells are e1iminated since display cells are all discharged and thenselected discharge cells are erased.

In addition, the vo1tage of the selection pulse for generating adischarge in the select cells can be a relatively low voltage becausethe wall charges generated in the display cells when the display cellsare fired, prior to the erasing operation, aid in generating a dischargein the select cells. Furthermore, a low voltage IC driving element canbe used to generate the select pulses since the firing voltage for theselect cells is generated by asymmetrical voltage pulses. Moreover, theelectrode arrangement described for use with the addressing method ofthe present invention allows sequential addressing of each line and asimplification of the driving circuitry without reducing the drivingspeed. Therefore, the addressing method of the present invention isbeneficial for driving a three-electrode type surface discharge displaypanel.

We claim:
 1. A method for addressing display cells of an A.C.three-electrode surface gas discharge panel having plural displayelectrode pairs parallel to each other and plural select electrodesinsulated from and arranged to intersect perpendicularly the displayelectrode pairs, the intersections of the select electrodes and onedisplay electrode in each display electrode pair defining a plurality ofselect cells and each display electrode pair defining plural displaycells between the display electrodes at positions adjacent tocorresponding ones of the select cells, and addressing method comprisingthe steps of(a) applying a firing voltage across display electrode pairto generate a discharge in the display cells defined by said displayelectrode pair; (b) applying a select voltage to selected selectelectrodes to generate a discharge in the select cells corresponding tonon-selected display cells in which the discharge is to be erased, sothat the wall charge in each of the non-selected display cells ineliminated; and (c) applying a sustaining voltage across the displayelectrode pair to sustain discharges in the selected display cells.
 2. Amethod for driving a gas discharge panel according to claim 1, whereinsaid step (c) further comprises applying an asymmetrical compositesustaining voltage so that the amplitude of the sustaining voltageapplied to the one display electrode which defines the select cell islarger than the amplitude of the sustaining voltage applied to the otherdisplay electrode.
 3. A method for driving a gas discharge panelaccording to claims 1 or 2, further comprising the step of sequentiallyperforming said step (a) for each display electrode pair in the panel,and sequentially performing said step (b) for each display electrodepair in the panel.
 4. A method for driving a gas discharge panel havinga plurality of display electrode pairs, a plurality of select electrodesinsulated from and arranged to intersect the display electrode pairs,one display electrode of each display electrode pair being connected incommon with the corresponding one electrode of other display electrodespairs to form at least one group, and the other display electrode ofeach display electrode pair being connected in common with thecorresponding other display electrode of other display electrode pairsto form at least one group, said method comprising the steps of:(a)generating discharges in display cells defined by a selected displayelectrode pair by applying a firing voltage across the selected displayelectrode pair; (b) erasing the discharge in non-selected display cellsdefined by the selected display electrode pair by applying a selectvoltage across the select electrodes defining select cells correspondingto the non-selected display cells and the other display electrode of theselected display electrode pair to generate a discharge in the selectcells corresponding to the non-selected display cells; and (c)sustaining the discharging of the selected display cells by applying anAC sustaining voltage to the selected display electrode pair.
 5. Amethod for driving a dischage panel having a plurality of paralleldisplay electrode pairs and a purality of selection electrodes insulatedfrom and arranged to intersect the display electrode pairs, theintersecitons of the select electrodes and one display electrode in eachdisplay electrode pair defining a plurality of select cells and eachdisplay electrode pair defining a plurality of display cells adjacent tocorresponding ones of the select cells, one display electrode of eachdisplay electrode pair being connected in common with the correspondingone electrode of at least one other display electrode pair to form agroup, and the other display electrode of each electrode in each groupbeing operated individually, comprising the steps of:(a) generatingdischarges in all of the display cells defined by the display electrodepairs forming a group; (b) generating discharges in all of the selectcells defined by the intersections of a selected select electrode andthe display electrode pairs forming the group; (c) selectively applyinga sustaining voltage to each display electrode pair in the group whichdefines a selected display cell adjacent to the select cell discharge insaid step (b); and (d) repeating said steps (b) and (c) for each selectelectrode.
 6. A method according to claim 3, wherein said sequentiallyperforming step comprises performing said step (a) prior to said step(b) for each display elecrode pair.
 7. A method according to claim 6,wherein said sequentially performing step comprises beginning thesuquential performance of said step (b) at the approximate time of thethird performance of said step (a).
 8. A method according to claim 4,further comprising the step of sequentially performing said steps (a)and (b) for each display electrode pair in the panel.
 9. A method ofdriving a gas discharge panel having plural display electrode pairs andplural select electrodes insulated from and arranged to intersect thedisplay electrode pairs, each display electrode pair including first andsecond display electrodes, the intersections of the select electrode andthe second display electrode of each display electrode pair defining aplurality of select cells and each display electrode pair definingplural display cells at positions adjacent to respective ones of theselect cells, said method comprising the steps of:(a) applyingsustaining voltage across a selected display electrode pair; (b)generating discharges in the display cells defined by said selectedelectrode pair; and (c) erasing the discharge in a non-selected one ofthe display cells defined by the selected display electrode pair bygenerating a discharge in the select cell corresponding to thenon-selected display cell, so that discharges are generated in selecteddisplay cells by the sustaining voltage.
 10. A method according to claim9, further comprising the step of sequentially performing sid steps (a),(b) and (c) for each display electrode pair in the panel.
 11. A methodaccording to claim 10, wherein said step (b) comprises generatingdischarges by superimposing a firing voltage on the sustaining voltage.12. A method according to claim 11, wherein said step (a) comprisesapplying an asymmetrical sustaining voltage, so that the amplitude ofthe sustaining voltage applied to the first display electrode is largerthan the amplitude of the sustaining voltage applied to the seconddisplay electrode.
 13. A method according to claim 12, wherein said step(c) comprises generating a discharge in the select cell corresponding tothe non-selected display cell by applying an asymmetrical select voltageacross the select electrode defining the select cell and the seconddisplay electrode, so that the amplitude of the select voltage appliedto the second display electrode is greater than the amplitude of theselect voltage applied to the select electrode.
 14. A method accordingto claim 13, wherein:said step (a) comprises applying a sustainingvoltage waveform having plural sustaining voltage pulses; and said step(c) comprises extracting the sustaining voltage pulse immediatelyfollowing the application of the select voltage from the sustainingvoltage waveform applied to the first sustaining electrode.